Track ball



FIG. 1 is a front elevational view of a track ball showing our new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a left side elevational view thereof, the right side is a mirror image; and,

FIG. 6 is a perspective view thereof. 

The ornamental design for a track ball, as shown and described. 